Sibylline Oracles is the name given to certain collections of supposed prophecies, emanating from the sibyls or divinely inspired seeresses, which were widely circulated in antiquity.

The derivation and meaning of the name Sibyl are still subjects of controversy among antiquarians. While the earlier writers (Eurìpides, Aristophanes, Plato) refer invariably to "the sibyl", later authors speak of many and designate the different places where they were said to dwell. Thus Varro, quoted by Lactantius (Div. Instit., L, vi) enumerates ten sibyls: the Persian, the Libyan, the Delphian, the Cimmerian, the Erythræan, the Samarian, the Cumæan, and those of the Hellespont, of Phrygia, and of Tibur. The Sibyls most highly venerated in Rome were those of Cumæ and Erythræa.

In pagan times the oracles and predictions ascribed to the sibyls were carefully collected and jealously guarded in the temple of Jupiter Capitolinus, and were consulted only in times of grave crises. Because of the vogue enjoyed by these heathen oracles and because of the influence they had in shaping the religious views of the period, the Hellenistic Jews in Alexandria, during the second century B.C. composed verses in the same form, attributing them to the sibyls, and circulated them among the pagans as a means of diffusing Judaistic doctrines and teaching. This custom was continued down into Christian times, and was borrowed by some Christians so that in the second or third century, a new class of oracles emanating from Christian sources came into being. Hence the Sibylline Oracles can be classed as Pagan, Jewish, or Christian. In many cases, however, the Christians merely revised or interpolated the Jewish documents, and thus we have two classes of Christian Oracles, those adopted from Jewish sources and those entirely written by Christians. Much difficulty is experienced in determining exactly how much of what remains is Christian and how much Jewish. Christianity and Judaism coincided on so many points that the Christians could accept without modification much that had come from Jewish pens. It seems clear, however, that the Christian Oracles and those revised from Jewish sources all emanated from the same circle and were intended to aid in the diffusion of Christianity. The Sibyls are quoted frequently by the early Fathers and Christian writers, Justin, Athenagoras, Theophilus, Clement of Alexandria, Lactantius, Augustine, etc. Through the decline and disappearance of paganism, however, interest in them gradually diminished and they ceased to be widely read or circulated, though they were known and used during the Middle Ages in both the East and the West.

Large collections of these Jewish and Christian oracles are still in existence. In 1545 Xystus Betuleius (Sixtus Birken) published an edition of eight books of oracles with a preface dating from perhaps the sixth century A. D. At the beginning of the last century Cardinal Mai discovered four other books, which were not a continuation of the eight previously printed, but an independent collection. These are numbered XI, XII, XIII, XIV, in later editions. Alexandre published a valuable edition with a Latin translation (Paris, 1841-56), and a new and revised edition appeared from the pen of Geffcken (Leipzig, 1902) as one of the volumes in the Berlin Corpus. In addition to the books already enumerated several fragments of oracles taken from the works of Theophilus and Lactantius are printed in the later editions.

In form the Pagan, Christian, and Jewish Oracles are alike. They all purport to be the work of the sibyls, and are expressed in hexameter verses in the so-called Homeric dialect. The contents are of the most varied character and for the most part contain references to peoples, kingdoms, cities, rulers, temples, etc. It is futile to attempt to find any order in the plan which governed their composition. The perplexity occasioned by the frequent change of theme can perhaps be accounted for by the supposition that they circulated privately, as the Roman Government tolerated only the official collection, and that their present arrangement represents the caprice of different owners or collectors who brought them together from various sources. There is in some of the books a general theme, which can be followed only with difficulty. Though there are occasionally verses which are truly poetical and sublime, the general character of the Sibylline Oracles is mediocre. The order in which the books are enumerated does not represent their relative antiquity, nor has the most searching criticism been able accurately to determine how much is Christian and how much Jewish.

Book IV is generally considered to embody the oldest portions of the oracles, and while many of the older critics saw in it elements which were considered to be Christian, it is now looked on as completely Jewish. Book V has given rise to many divergent opinions, some claiming it as Jewish, others as the work of a Christian Jew, and others as being largely interpolated by a Christian. It contains so little that can be considered Christian that it can safely be set down as Jewish. Books VI and VII are admittedly of Christian origin. Some authors (Mendelssohn, Alexandre, Geffcken) describe Book VI as an heretical hymn, but this contention has no evidence in its favour. It dates most probably from the third century. Books I and II are regarded as a Christian revision of a Jewish original. Book VIII offers peculiar difficulties; the first 216 verses are most likely the work of a second century Jew, while the latter part (verses 217-500) beginning with an acrostic on the symbolical Christian word is undoubtedly Christian, and dates most probably from the third century. In the form in which they are now found the other four books are probably the work of Christian authors. Books XII and XIII are from the same pen, XII being a revision of a Jewish original. Book XI might have been written either by a Christian or a Jew in the third century, and Book XIV of the same doubtful provenance dates from the fourth century. The general conclusion is that Books VI, VII, and XIII and the latter part of Book VIII are wholly Christian. Books I, II, XI, XII, XIII, and XIV received their present form from a Christian. The peculiar Christian circle in which these compositions originated cannot be determined, neither can it be asserted what motive prompted their composition except as a means of Christian propaganda.